TPG Telecom has disclosed a breach of hosted Exchange services that run email accounts for up to 15,000 iiNet and Westnet business customers.
The telco said that Mandiant had “found evidence of unauthorised access” on December 13.
The target appeared to be “cryptocurrency and financial information” contained within accounts, TPG Telecom said in a financial filing.
It appears the incident was identified as part of routine scans on networked assets.
“As part of Mandiant’s ongoing engagement to assist with cyber protection, they conducted a forensic historical review and discovered the unauthorised access to the hosted Exchange service,” TPG Telecom said.
“We have implemented measures to stop the unauthorised access, further security measures have been put in place, and we are in the process of contacting all affected customers on the hosted Exchange service.
“The matter remains under investigation and we will be communicating with directly affected customers as more information becomes available.”
TPG Telecom said it had notified “relevant government authorities”.
It apologised to business customers for the incident. It also said that residential customers of the two brands are not affected.
